AB0128 DIFFERENTIAL EXPRESSION OF PROTEINS IN PATIENTS WITH SUSPECTED SJÖGREN’S SYNDROME
Authors: M. J. Santos-Bornez, M. Fernandez Castro, C. Merino Argumánez, J. Sanz, J. Campos Esteban, N. De la Torre Rubio, P. Navarro Palomo, M. Pavía Pascual, M. Machattou, M. C. Sánchez Fernández, P. D. Briongos Díaz, H. Godoy, B. Garcia-Magallon, C. Barbadillo Mateos, L. F. De Villa, C. Isasi Zaragoza, J. L. Andréu Sánchez, A. Sánchez
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Sjögren's Syndrome (SS) is a chronic systemic autoimmune disease characterized by involvement of the exocrine glands in addition to a wide spectrum of systemic manifestations. At present, conventional biomarkers do not respond to unresolved needs regarding diagnosis, stratification of phenotypes and appropriate effective therapies<sup>[1]</sup>. SS is an orphan disease and new biomarkers could constitute potential future therapeutic targets<sup>[2]</sup>. <h3>Objectives</h3> The purpose of this study was to carry out an exploratory analysis in six serum and saliva samples from suspected SS patients to identify protein biomarkers to distinguish SS patients who were diagnosed with SS from those who were not. <h3>Methods</h3> We selected six patients from a cohort of 199 consecutive patients attended the rheumatology department for suspected SS: 3 patients who met SS classification criteria from 2002 and/or 2016 who were diagnosed with SS by a rheumatologist and 3 patients who did not meet SS classification criteria who were not finally diagnosed. Serum samples were collected and centrifuged at 1800g, divided into aliquots and stored at -80ºC. Saliva samples were cold collected to prevent degradation of proteins, centrifuged at 1800g at 4ºC and stored at -80ºC. A semiquantitative analysis of protein expression was performed using the "Proteome Profiler Human XL Cytokine Array Kit" arrays from R&amp;D system that detects 105 proteins containing interleukins, chemokines, inflammatory factors and other soluble proteins. Analytes optical densities were quantified using Image J software. The content of the analytes was compared between SS patients and non-SS patients using an unpaired Student´s t test and a measure of the odds of an analyte happening in one group compared to the odds of the same analyte happening in another group (OR: odds ratio) is shown. Statistical analysis were performed using Microsoft Excel software. <i>P</i> values ≤0.05 were defined as significant and values of 0.1&lt;<i>P</i>&gt; 0.05 were considered as borderline. <h3>Results</h3> We found increased serum levels of CD14 (OR:1.21; <i>P</i>=0.033), EGF (OR:1.18; <i>P</i>=0.050), IP-10 (OR: 1.23; <i>P</i>=0.090) Pentraxin 3 (OR:1.32; <i>P</i>=0.095) and VEGF (OR:1.41; <i>P</i>=0.091) in patients diagnosed with SS who met SS classification criteria, compared with patients who did not meet SS classification criteria who were not diagnosed, although only in the case of CD14 and EGF, statistical significance was reached. In saliva samples, we found significantly increased values of ICAM1 (OR: 1.67; <i>P</i>=0.019), IL-6 (OR:1.20; <i>P</i>=0.042) and IL-19 (OR:1.51; <i>P</i>=0.039) in patient who did not meet SS classification criteria. compared with patients who did. <h3>Conclusion</h3> Sjögren's syndrome patients presented significantly higher levels of CD14 and EGF in serum, as well as significantly decreased levels of ICAM1, IL-6, and IL-19 in saliva, when compared to patients who did not meet SS classification criteria. It is necessary to confirm these results in a larger cohort of patients. <h3>References</h3> [1]V.C. Pezoulas <i>et al</i>. <i>Computational and Structural Biotechnology Journal</i>; 2022;20:471–484. [2]V. Manfrè <i>et al</i>. Sjögren's syndrome: one year in review 2022.<i>Clin Exp Rheumatol;</i> 2022; 40: 2211-2224. <h3>Acknowledgements</h3> To all the patients who have participated in this study. <h3>Disclosure of Interests</h3> None Declared.